parseBoolean

parseBoolean是包装类下Boolean下的方法，为了更明白一些，我们来看一下源代码

 /**
     * Parses the string argument as a boolean.  The <code>boolean</code> 
     * returned represents the value <code>true</code> if the string argument 
     * is not <code>null</code> and is equal, ignoring case, to the string 
     * {@code "true"}. <p>
     * Example: {@code Boolean.parseBoolean("True")} returns <tt>true</tt>.<br>
     * Example: {@code Boolean.parseBoolean("yes")} returns <tt>false</tt>.
     *
     * @param      s   the <code>String</code> containing the boolean
     *                 representation to be parsed
     * @return     the boolean represented by the string argument
     * @since 1.5
     */
    public static boolean parseBoolean(String s) {
        return toBoolean(s);
    }

所以：

public class test {
	public static void main(String[] args){
		String s = "true";
		boolean a=Boolean.parseBoolean(s);
		System.out.println(a);
	}
}

结果为：true

而当s为其他的值时，结果为：false

应该常看java的源代码，这样能理解最深层的原因。